Fluid clutch



Oct 16, 1945.` c.- A.' sAw'rELLE 2,386,912

FLUID CLUTCH Filed July 5, 1945 5 Sheets-Sheet l Snventor 0d. 16, 71945 c. A. sAwTELLE 2,386,912

FLUID CLUTCH Filed July 5, 1943 3 Sheets-Sheet 2 lSnvenfor Chr/e; ASawte/Ze Gtforneg Ott. 16, 1945. C, A. SAWTELLE 2,386,912

` n FLUID CLUTCH Filed July 5, 1943 5 Sheets/Sheet 3 Btlmcutor V J- I (Ittornexi Patented Oct. 16, 1945 UNITED srAresrAreNr OFFICE-y g FLUID CLUI'rcH- Charles" Sawtelle, Rosedale Gardens,Mich. I.

Applicationauly 5,1943,serialNo.493,617y Y I f sjolaims.y (el. 19a-5s) This invention relates to clutches and particularly fluid clutches. 'jf An object of thev invention is toprovidela clutch eliminating the usual friction aC'sand thus avoiding loss of time and 'material involved by replacement of linings, and eliminating unsatisfactory clutch response vdue to excessive lining wear. "i I' Another object is to providefaclutch employ ing a fluid medi-um to transmit torque and con-4 sequently permitting slippage between the driving and driven members, whereby the stresses and shocks incident to load applications 'are `re` duced and the clutch may serve to reduce the speed of a driven member below that of the driv-v ing member. It is to be noted in this connection that slippage of friction face clutches is objectionable and generally avoided. Y,

Another object is to provide a fluid clutch vof such simple construction that its cost will com--` pare favorably with that cfa friction face clutch. Another object is to render a motor vehicle fluid clutch so compact as to permitvits installation within the usual flywheel of a vehicle motor. These and various other objects are attained by the construction hereinafter described and ill lustrated by the accompanying drawings, whereline 2-2 of Fig. 3, and showing the clutchreleased. y l

Fig. 3 is a diametrical sectional view of the clutch taken on the line 3-3 of Fig. 2. Y

Fig. 4 is an end elevational View, partially in section on line 4-4 of Fig. 3 and showing the clutch applied.

Fig. 5 is a radial section of Fig; 4. v y

In these views, the 'reference character I des: ignates a flywheel comprising "a radial web' secured by bolts 2 to one end Yof a shaft'3 which may be driven'by'an engine (not Shownl" or in any other desired manner. Said flywheel serves as a mounting for my improved clutch through which a drive may be established when desired to a shaft# aligned with-the shaft 3 and having a reduced end portion 5 set into and journaled taken on the line 5-5 in the shaft 3. VThe flywheel rim is exteriorly annularly ribbed, as indicated at 6 to promote heat dissipation, said rim being integrally carried bythe web at one side thereof. Rigidly mounted on the fiywheel'rim at its margin remote from the'web is an annular plate I extending some distance radially inward` from the Fromthe inner margin of the plate 1 an annulus 8 extends within the iiywheel toward the web thereof and-a plate 9, integral with and inwardly extending" from said annulus,v is parallel to 'and spaced fromthe ywheel web Vand is centrally apertured to freely accommodate the shaft II. A plurality of bolts I0, headed against the outer face 'of the plate I are threaded into'bosses YIIV interiorly Vformed on the Aflywheel rim, to mount thefmember I, 8,'9 rigidly onsaid rim. Y

An y. annular chamber I2 is formed within the outer portion of the flywheel by the plate 'I and annulus 8 in conjunction with thevywheelrim and web, the inner portion of such chamber vbe.. ing occupied bya fluid-driven clutch 'ringv I3, which mounts a plurality of radially .sliding vanes- TIA formedpreferably of hardened steel. Said'vanes, wherec fi nine are' employed in the disclosed construction, are preferably set' into guides` l I5 projecting integrally inward from the ring I3,the inner end portions of each .vane bein'gVr radiallyslotted to' accommodate a pair 'of coiled springs I'a compressed between Vthevane and Yinnerportion ofthe corresponding guide and urging the* vane yieldably Voutwardl The radial edges of the v'anes have a fluid-sealing contact with the flywheel web and plate I and thesame istruefof annular "sealing rings II and` I8 formed integrally with the ring I3 andinterconnecting th'e guides I5.` The ring I8 is not conned tothe chamber`l2, as is the ring` I 'I,y Ibut extendsinwardly between the `lywheel web and plate 9, and is 'splined on the shaft 4, serving to transmita drive 'from the ring I3 to said shaft. Surrounding the clutch ring I3 and normally spaced' slightly Voutward therefrom isa flexible band `I'lljpreferably'of spring steel, with whichV the outer edges of the vanes I4 have fluid-seal# ing cnt'act'the edges of said band having sealing contact with the flywheel `web and plate 1v. Said'rballd, when' not forcably distorted, tends t assume circular formas appears in Fig. 2,'bein'g then'inwardly spaced from annular shoulders 20 oppositely formed on the flywheel web and plate TI'- tolimit outward distortion ofthe bandj AA drive from the flywheel to said band is permanently established bya plurality of f'l'lshaped arms ZI, equidistantly `circlimferentiallyspaced, threelbe-V ing employed in the illustrated construction.

Said :arms are mounted in the outerportionof the chamber I2 in Va tangential relation to the band I9, one end of eacharm being formed with aboss 22' tted in an opening 23 of theband and its other lend having lateral extensions .24 engag-v the flywheel web and plate 1.

ing blind bearing sockets 25 formed respectively in the flywheel web and plate 1 to pivot the arm. Outwardly from its boss 22, each arm is engaged by a rock shaft 2B transversely grooved at 21 to accommodate the arm,Y and journaled jointly in It is preferred to form the plate 1 with exterior bosses 28 to accommodate the rock shafts and to dispose in each boss a ball bearing 29 and a uid seal 3U. Each rock shaft projects'suiciently beyond the corre.- sponding boss 28 to'rigidly carry ahead 3I clon;- gated transversely of such shaft to form two blind sockets 32 opening approximately towards the shaft 4, said sockets being oppositely spaced from the rock shaft axis. of each head 3l is the outer end of an approximately radial pin 33, guided at its inner end by a lug 34 integrally projecting from the plate 1., said pin being yieldably subjected to outward pressure by a spring 35 coiled about said pin and compressed between its headed outer end vand said guide lug. Thepin has suicient looseness in said lug to afford it such angular play in the plane of rotation of the clutch` as is incident to a required-rocking of the-head 3l.VA The other socket'32 of each head 3I receives the ball-headed outer end-of atoggle pushrod 35, the inner endsof the three push rods being individually pivotallyconnected, as indicated at 31,V to a collar 38, the, axes of the connections 31 being tangential to the collar. Y The latter is splined-upon a sleeve 39`integrally and centrallyrprojecting from the plate 9, in a free surrounding relation tothe shaft 4. A coiledspring 4U compressed between saidcollar and an abutment 4I on the free end 'of theY sleeve urges the collar toward the flywheel-and'tends to lodge thecollar against an annular exterior rib 42 on the sleeve. In this poe sition of the collar, the push rods 36 have a very slight Acon'vergency toward the liywheel, from their outer to their inner ends,'as shown in dash lines in Fig. -3. The collar may be actuated to its position-shown in full lines in Fig. 3 'by a yoke 43 `ixed on a rock shaft M and engaging a ring 44a in an annular groove 45 in the collar. Such actuation relieves stress on the push rods, by establishing them ata material divergency to the fly-Wheel, `from .their outer to their inner ends. Rocking of the shaft 44 to retract the collar 38 against resistance of the spring 40 may be accomplished inany desired manner, as by the usual clutch pedal (notshown) of'a motor vehicle. f

' It is to'beunderstood that the annular space between the clutch ring I3 and band- ISk is' filled with oil or some other suitable liquid and a normally plugged 'llf opening 46 `may be provided for renewal of such liquid if and when required. 'In use of the described clutch, the spring 4D normally holds the collar 38 against the abutment 42, thus maintaining the push rods 3B substantially transverse to the clutch axis, as per dash line showing in Fig. 3. Henceqthe ends of the heads' 3| engagedby the push rods are normally outwardly rocked while the pins 33 are thrust toward the clutch axis, compressing the springs 35. In their resulting position, the rock shafts 26 bear on the arms 2|, as shown-in Fig. 4, at terminal edges of the grooves 21 acting through said arms to apply an inward pressure to the flexible band `I9 whereby the latter is held rmly against the ring I3. This inward distortion of the band from'its inherent circular form at equidistant points induces an expansion of the band between'such points, as clearly appears in Fig. 4. The vanes I4 slidingly adjust themselves Entered in one of said sockets'- differentially to the band, while maintaining constant Huid-sealing engagement with it. The bulging of the band between the three points of its inward distortion may also be regarded as due to a redistribution of the liquid conned between the band and clutch ring I3.

With the parts positioned as described, it is evident that the band I9, as driven by the flywheel through arms 2l has portions traveling the cir- Cumferential-.path occupied by the liquid and that theliquidtannotbe displaced by said portions, being conned in the chambers formed between the Vanes and between the band and clutch ring v -driving the clutch ring which in turn drives the shaft 4.

'When the collar 38 occupies its clutch-releasing position, as per full line showing in Fig. 3, the push rods 36 are relieved of material thrust and the springs acting through the heads 3l on the rock shafts 26, establish the latter in the positions shown in Fig. 2, relieving pressure on the arxnsZl and hence on the band I9. Upon relief yof such pressure the band resiliently returns to `its inherently circular form, continuing to conne the liquid but ceasing to apply any material torque to the latter.

The clutch, as shown in Fig. 4 and in dash lines in Fig. 3, establishes a full drive as will commonly be desired. Numerous conditions'will arise, however, rendering a partial drive vtemporarily advantageous. For example, a car equipped with the described clutch may be. required to climb a short hill involving such an increase of motor load` as would ordinarily entail Vshifting'into second gear. Such necessity may be avoided by partially releasing the clutch so that slippage thereof results in a' Speed reduction of the transmitted drive. .With the clutch partially applied, a distortion of the band is elfected but not a maximum distortion such as brings theband into contact with the ring I3. Thus a regulated portion of the liquid will travel reversely to the direction of clutch rotation and reduce torque transmission toany 'desiredextent. By reducing the frequency of shifting gears, the improved clutch will materially reduce wear on the gears, giving the latter agreater life and rendering driving less arduous. i.. Iu engaging the described clutch under all conditions, a greater smoothness of driving is avail'- able, since necessity is eliminated fo-r an abrupt application of full load as in present practice and the increase of i torque transmission may be so distributed over a suitable time interval as to avoid any jerking or sudden stress on a motor vehicle with resultant discomfort to the occupants,- e

Moreover, the described clutch will greatly facilitate starting a Vehicle on an icy or other slipperyfsurfaee or in picking up any abnormally heavyload, since thev application of torque to the driven wheels may be accomplished so gradually as ytorninimizetheir tendency 4to spin.

It will be noted'that the grooved faces of the rock shafts 2,6 havea camming action in apply.- ing pressure tothe arms'ZI, the angle between said grooved faces and the arms never being great enough to effect locking of the arms` Thus upon release of the clutch, the expansive tendency of the band supplements the springs 35 in effecting such'rotation of the vrock shafts as permits the band to 355.11m@ Circular' form f' 'lt isfurtber t0 be noted that when the rock shafts are in their clutch-applying position, they are locked in that position by the push rods 36 since the latter are then substantially transverse .to the clutch axis and cannot yield responsive to any fluid-induced effort of the band -to overcome distortion applied by the rockshafts. Since the inclination of the push rods is to a slight extent reversed when the collar 38 assumes its clutchapplying position, any stresses reacting` through the push rods upon the collar tend merely to seat it more firmly against the abutment 42.

What I claim is:

1. A fluid clutch comprising coaxial rotary driving and driven members, an annulus conned between said members in a substantially coaxial relation therewith, and forming with one of said members a fluid chamber, and flexible to and from the last-mentioned member, a liquid conned in said fluid chamber, a plurality of blades mounted in circumferentially spaced relation upon the last-mentioned member and slidable through said fluid chamber to and from said annulus, means permanently and positively connecting said annulus to the other of said members for rotation therewith, means yieldably acting on the blades and maintaining fluid-sealing contact thereof with the annulus, and means for imposing and relieving pressure upon circumferentially spaced portions of said annulus to flex such portions into or out of engagement with the blade-mounting member, 'and' thereby afford a transmission of torque through said liquid.

2. A uid clutch as set forth in claim 1, said means for imposing and relieving pressure on the annulus taking eifect through said means connecting the annulus to the other of said members for rotation therewith.

3. A fluid clutch as set forth in claim 1, the annulus being apertured for engagement by said means connecting the annulus to the other of said members for rotation therewith.

4. A fluid clutch comprising coaxial rotary driving and driven members, the driving member being chambered to receive the driven member, an annular band substantially coaxial with and disposed between said members and flexible to and from the clutch axis, a set of blades circumferentially spaced and slidable substantially radially on one of said members and having edges in fluidsealing engagement with said band, means permanently and positively connecting the band to the other of said members to rotate in unison with such other member, springs effective on said blades to maintain their engagement with the band, a liquid for transmitting a drive from the Adriving to lthe driven member, occupying a substantially annular space between said band and the member wherein the blades are slidable, such space being subdivided by the blades, and means for radially exing the band at least at one point around its circumference into engagement with the blade-mounting member whereby the band coacts with certain of the blades to trap portions of said liquid,` and the liquid so trapped transmits a drive from the driving to the driven member.

5. A iiuid clutch as set forth in claim 4, said means connecting the band to the other of said members comprising arms disposed substantially in a tangential relation to 'the band and pivoted at corresponding ends thereof to rock as the band is flexed and thus adapt themselves to such flexure.

6. A huid clutch comprising an outer rotary driving member, an inner rotary driven member, an annular body of liquid engaging one of said members, a iiexible annulus coacting with the last-mentioned member to confine said liquid body, such annulus being normally circular, a permanent and positive drive connection from the driving member to said annulus', radially 'slidable torque transmission ,nelements carried by the driven member and extending through said liquid body into sealing engagement with said annulus, and means for flexing said annulus at circumferentally spaced points thereof toward the driven member to establish a drive from the annulus through the liquid to said elements.

7. A fluid clutch comprising coaxial rotary driving and driven members, a radially flexible annulus confined between said members in a substantially coaxial relation therewith and forming with one of said members a fluid chamber, a liquid confined in said fluid chamber, a plurality of blades mounted in circumierentially spaced relation upon the last-mentioned member and slidable through said fluid chamber to and from .the annulus, a plurality of arms spaced circumferentially of the clutch and extending tangentially with respect to said annulus and establishing drive connections to the annulus from the other of said members, means adapting said arms to rock to and from the axis of the clutch,"

a rotary cam effective on each of said arms to distort the annulus into engagement with the blade-mounting member, and means for concurrently rocking said cams.

8. A fluid clutch comprising coaxial rotary driving and driven members, a radially flexible annulus confined between said members in a substantially coaxial relation therewith and forming with one of said members a fluid chamber, a liquid confined in said Iiuid chamber, a plurality of blades mounted in circumierentially spaced relation upon the last-mentioned member and slidable through said uid chamber t0v and from the annulus, a plurality of rock shafts spaced circumierentially of the clutch and lying substantially parallel to the clutch axis, cams on said rock shafts effective on the annulus to ex it from a normally substantially circular idling position to a distorted drive-transmitting position of engagement with the blade-mounting member, a head on each rock shaft extending in opposite directions from such shaft, a plurality of push rods radiating from the clutch axis and engaging said heads at corresponding sides of the rock shafts for rotating the cams to ltheir annulus-flexing position, springs effective on said heads at the othersides of the rock shafts opposing the rotation applied by said rods, and means for shifting the inner ends of the rods in unison along the clutch axis to control the effect of said rods on the rock shafts.

CHARLES A. SAWTELLE. 

